Stringed musical instrument



June 9, 1931.

e. D. BEAUCHAMP STRINGED MUSICAL INSTRUMENT Filed Jan. 21, 1930 2Sheets- Sheet A TTORNE X8? June 9, 1931.

G. D. BEAUCHAMP 1,808,757

STRINGED MUSICAL INSTRUMENT Filed Jan. 21, 1930 2 Sheets-Sheet 2 a INVEN OR.

A TTORNE Y Patented June 9, 1931 UNITED STATES PATENT OFFICE STBINGEDMUSICAL INSTRUMENT Application filed January 21, 1930. Serial No.422,337.

This invention relates to stringed musical instruments .embodyin thinmetallic resonators ordiaphragms a apted tobe tensioned against orconnected with the strings in such a manner that the vibrations set upin the strin s when the instrument is played will be su stantiallyamplified and the volume of the instrument increased.

'An'object of my invention is to provide in such an instrument animproved type of diaphragm so formed that a single large diaphragm maybe employed in lieu of a plurality of smaller diaphragms. It will beunderstood that in instruments of the type mentioned the size of thediaphragms influences the quality and volume of the tones produced bythe instruments. That is to say, that diaphragms of the charactergenerally used which are conical in form and are con 2 nected with thestrings at their apexes become inefficient as amplifiers or resonatorsas their diameters are increased beyond certain limits. In casediaphragms of excessive diameter are employed the vibrations which 26emanate from the strings and are distributed to the diaphragms at theiraxes are dissipated before they reach the peripheries of the diaphragms.It is, however, desirable to provide in an instrument of the charactermentioned a single diaphragm in lieu of a plurality of diaphragms forthe reason that a single diaphragm lends itself to a more economical andsimple construction.

Accordingly this invention comprehends 36 the provision of an improvedform of diaphragm of relatively large diameter as compared to diaphragmsusually employed in such instruments. My improved diaphragm 7 may besaid to be generally of conical cross section, but includes a pluralityof smaller conical portions or expressions integral with the main conebut having their axes arranged at points intermediate the axis and theperiphery of the diaphragm. In this type of v construction thevibrations from the strings are communicated to the apexes of thesmaller conical portions at points nearer the periphery of the main conethan would be possible were the strings connected with the apex of themain cone. Furthermore, there being a plurality of the conicalexpressions the vibrations from the strings are communicated at aplurality of points, preferably concentric with respect to the axis ofthe main cone, thus insuring a uniform distribution of the vibrationsthruout the diaphragms.

This construction also provides clarity and quality of tone comparablewith that obtained by the use of a plurality of separate diaphragms.

Another object is to provide an improved body structure for mounting thecomposite diaphragm in operative relation with the strings.

Other objects may appear in the description hereinafter following.

In the accompanying drawings I have shown a preferred form of myinvention, in which Fig. 1 is a top plan view of an instrument embodyingmy improvements.

Fig. 2 is a transverse section of the same on line 22of Fig. 1.

Fig. 3 is a fragmentary section of the instrument on line 33 of Fig. 2.

Fig. i is an enlarged sectional plan of a diaphragm and supporting meanstherefor on line H of Fig. 2. v

Fig. 5 is a top plan View of a diaphragm.

Fig, 6 is a side elevation of the same.

The body of the instrument is preferably formed of thin sheet metal withthe top 1 and bottom 2 substantially spaced apart and connected by acontinuous side portion 3. A neck 4 and a tail piece 5 are suitablysecured to opposite'ends of the body and serve to support a plurality ofstrings 6, 6 etc., in tension over the top 1. The top of the body has adepressed central portion 7 integrally formed therewith and providedwith an in- Wardly turned flange 8 at the bottom, thus forming a shallowcompartment 9 at the top of the instrument, in which is held a singlediaphragm 10.

The top 1 is counter-sunk at 11 at the upper side of the depression 7 soas to provide a seat for a plate 12 which closes the upper side of thecompartment 9 and is attached to the body by means of screws or rivets13.

i The plate 12 has a central aperture 14 and a internally: of the flangeplurality of sets of apertures 15 therein thru which the tones of theinstrument emanate. The diaphragm 10 is generally of conical crosssection and has a peripheral flange 15 adapted to sea-t on the flange 8of the body. One or more annular beads 16 may be formed 15 for renderingthe diaphragm sufliciently flexible and. fmore. sensitive to vibrationsth n would be possible Withoutthe beads. 1 4

The diaphragm 10 is supported onthe portion 7 at the top with itsconcave side downward and its convex side upward, and is formed with aplurality of conical portions 17, 1 T-etc concentriea ly arranged aboutthe axis thereof. tersect the main cone of the diaphragm 10 and arepositioned with theiraxesintermediate' the axis and theperiphery of themain cone. 'A spider 18 is mounted on the diaphragm 10 and is providedwith a plurality of'arms 19, 19 etc., with terminal portions 20, 20etc., formedthereon which are adapted torest upon the. apexes oi the.portions 17. I may provide apertures at-the apeXes of thecportions 17 to.receive teats as at21, so

that the spider 18 will be incapable ofdis-- placement from operative.position'onthe diaphragm. .I prefer to arrange the spider 18 with two ofthe arms 19, 19 in longitudinal alinement andthe other at right anglesthereto, as shown inFig. 4, especially- Where three of the conicalportions 17 are provided on the diaphragm. By this means I may groovethe right angularly disposed arm 19 of the spider to receive awooden-bridge 22-. Thus the spider 18 supports the bridge 22 infrictionalengagementwith the strings 6,

as shown in Fig. 3, and-the strings are tensioned over the bridgeas'usual. f It will be noted that the bridge 22 extends upwardly thruthe central opening 1 in the plate 12 and I provide a guard 23 formed.of flat strap metal which extends transversely over the strings6 and theopening-14 andis bent downwardly at its ends and 'fsuit ably secured] tothe plate 1 The, guard 23' also serves as a hand rest-for theoperatorwhenthe instrument-is being played. From theforegoingdescription of my invention, considered with the illustrationsof the drawing, it will be apparentthat by communicating the vibrationsfrom'the; strings 6 to the apeXes of the-conical portions17 inthediaphragm 10, particularly at points 'outwardlyofthe axis of thediaphragm, the

vibrations-will more readily traverse the distances from the apexes ofthe-smaller cones to the outer periphery of the maincone than they wouldfrom the axis to the periphery of the main cone, and 1 substantially thesame 7 quality of tone will be provided ina-single All diaphragm whichwould otherwise be provided in a multiple diaphragm. instrument.

The conical portions 17 iii-- The supporting portion 7 of the body has alarge central aperture 24 therein so that body, and havingaplurality ofportions at central points arranged to support said strings,ton-thepimpose. described;

v 2. A stringed. musical instrument: com-. prising. a body havings.ringsheldthereon .in tension,"a diaphragm. mounted in said. body;

and provided with apluralityof conically' formed portions, andmeansengagingco1me+ sponding points of said portionsand alsoengagingsaid strings, :forthe purpose de-v scribedm v 3. A stringedmusical/instrument;comprise. ing a body having stringsiheld thereon. intension, a diaphragm. having. a plurality. of cones formed thereon andhaving-faxes intermediatethe axis. and. periphery otthe diaphragm, andmeans. intermediate the. axes .of

said cones andsaidstrings forcommunicating the vibrations from. the'stringsx to the dia:

phragm.

4. A" strin edimusical?instrumenti incluch ing a body havingstringsad-aptedto beheld in tension thereon, a. unitary V diaphragmformed'i'ot sheet metal supported; at its. periphery on said body andprovided with a plurality of portions bent outwardly. from itsperiphery, and :mea'nsengaging saidoute wardlybentportionsand'saidgstrings, for. the

purpose described I 5. A stringed musical instrument comprising a bodyhaving strings held in tension thereon, a metal chaphragm supported at.its periphery on said body and provided with a plurality of portions:bent outwardly from the planeofits periphery, and. common means engagingcorrespondingpoints on said outwardly-bent portions-- and engag ng saidstrings, forthepurpose described.

- 6.- In stringed mus-ical' instrument, 7 a metal d aphragmh-avlng aperipheral supporting flangeand a-plurality of outwardly bent=cones withaxes concentric with theaxis of the diaphragm. V 7'; In a stringedmusical instrument, adiaphragm in the form ot-a shallow'conehaving aperipheral supportingportion anda plurality of conical portionsintersecting the main cone and arranged with thei-raXes concentric; withth'eaxis'oztthe main-cone. 8. Astringed musical instrument comprisin-gabody having its top bent-downwardly and inwardlyto provide a support,1aplate secured to the top of said body, strings held in tension over saidplate, a diaphragm held at its periphery on said support and having aplurality of cones bent outwardly from the plane of the periphery ofsaid diaphragm, and common means engaging corresponding portions of saidcones and said strings, for the purpose described.

' 9. A stringed musical instrument comprising a body having its top bentdownwardly and inwardly to provide a support, a plate secured to the topof said body, strings held in tension over said plate, a diaphragm heldat its periphery on said support and having a plurality of cones bentoutwardly from the plane of the periphery of said diaphragm, and commonmeans engaging corresponding portions of said cones and said strings,said means including a spider in contact with the diaphragm, and abridge intermediate said spider and said strings, for the purposedescribed.

10. A stringed musical instrument comprising a body having its top bentdownwardly and inwardly to provide a support, a plate secured to the topof said body, strings held in tension over said plate, a diaphragm heldat its periphery on said supportand havin a plurality of cones bentoutwardly from t e plane of the periphery of said diaphragm, commonmeans engaging corresponding portions of said cones and said strings,said means including a spider in contact with the diaphragm, a bridgeintermediate said spider and said strings, said plate having an openingthru which said bridge extends, and a guard secured to said plate andoverlying said strings.

GEORGE D; BEAUCHAMP.

